Insulator apparatus for vacuum insulated tubing

ABSTRACT

An insulating apparatus for use with vacuum insulated tubing sting to reduce heat loss through the joints, where the apparatus includes an insulator adapted to surround the joint and a latching joint protector adapted to surround the insulator and hold the insulator against the joint, where the protector also includes a channel for receiving injection and/or control tubing. The insulator is capable of reducing heat loss through the joints of a vacuum insulated tubing string by as much as 95%.

RELATED APPLICATION

[0001] This application claims the benefit of provisional priority toUnited States Provisional Patent Application Serial No. 60/434,903 filed20 Dec. 2002.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to an insulator apparatus forvacuum insulating tubing.

[0004] More particularly, the present invention relates to an insulatorapparatus for vacuum insulating tubing adapted to provide insulation atjoints in a vacuum insulating tubing string including an insulatingmember and a joint protector surrounding and holding the member in placeat the joints.

[0005] 2. Description of the Related Art

[0006] In the petroleum industry, production tubing is disposed within aborehole for transporting oil and gas from subsurface bearing formationsto the surface. This tubing is comprised of elongate sections threadedtogether to form a production string, the joint thereby formed beingreferred to variously as a tool joint, coupling, or upset.

[0007] In conjunction with this production tubing, it is frequentlynecessary to provide a system for delivering fluid media downhole. Onereason may be to permit the injection of chemical treatment fluids nearthe producing formation for enhancing the production, for treatment ofdownhole conditions such as those involving undesirable corrosion, salt,or scale, and for delivery of corrosion or scale inhibitors,de-emulsifiers, or the like, downhole.

[0008] Yet another reason for providing these fluid delivery systems isfor the transmission of fluid pressure to various downhole valves ortools from the surface for purposes of control or the like. Thus,various forms of injection or control lines referred to hereinaftergenerally as tubing and having internal diameters much smaller than thatof the production tubing itself are provided which are disposed radiallyoutward of and adjacent to the production tubing. In some cases thetubing is of an encapsulated variety wherein both the tubing and wirerope (which provides crush resistance from side forces) are encapsulatedin an appropriate thermoplastic elastomer, whereas in otherapplications, the tubing may be of an unencapsulated or bare variety.

[0009] In other situations, electrical cables are routed downhole inlike manner to the tubing for monitoring pressure instruments or forproviding power for downhole motors or the like.

[0010] One problem with these tool joints and the associated tubing orcables (referred to hereinafter as tubing for convenience) is that theyare frequently subjected to damage from contact with surrounding casingor the formation itself, such as when the production string is moved upor down within the borehole. This damage may be due to abrasion orcompressive forces against the joint or tubing which often occurs as thetool joint is moved across a deviation in the borehole. Thus, means weresought for protecting this bare or unencapsulated tubing, cable and thetool joints from damage.

[0011] In deep water drilling operations, one difficulty in producingoil from such deep wells is the loss of heat associated with the oil asit flows out of the productive formation into the production tubingresulting in proportional increase in fluid viscosity and reduced wellproductivity. One answer to this vexing problem was the advent of vacuuminsulated tubing, which provides a vacuum break between the productiontubing and the outside world, greatly reducing heat loss as theproductive fluid is communicated to the surface. However, heat loss isstill a problem at the joints of the tubing where, out of necessity, thejoints are not insulated and therefore heat can flow out of the jointsto the surrounding.

[0012] Thus, there is a need in the art for an apparatus that can beattached to at the joints of vacuum insulated tubing insulating thejoints from the outside world, while providing a protected conduit forproduction communication cables or other production wirelines.

SUMMARY OF THE INVENTION

[0013] The present invention provides an insulator apparatus for usewith vacuum insulated tubing strings, where the apparatus includes aninsulator adapted to insulate joints in the vacuum insulating tubingstring and a joint protector adapted to secure the insulator against thejoints, to protect the joints from damage during run in and run out andto provide a protected conduit adapted to receive injection or controltubing associated with the vacuum insulated tubing.

[0014] The present invention also provides an apparatus for protectingand insulating joints in a vacuum insulated tubing string, where theapparatus includes an insulator sleeve having a longitudinal slit, asubstantially smooth outer surface, and an inner surface that conformsto an outer contour of the joint and to a portion of the tubing oneither side of the joint. The apparatus also includes a joint protectorhaving a first latching end and second latching end where the latchingends are adapted to secure the protector to the vacuum insulated tubingstring on both sides of the joint. The protector also includes a centerregion having a insulator retaining member or a plurality of insulatorretaining members, where the center region is adapted to hold theinsulator against the joint. The protector also includes a conduitadapted to receive injection or control tubing allowing injection and/orcontrol tubing to pass over the joint in a protected manner. Theinsulator can also include a strip of adhesive adapted to seal thelongitudinal slit. Alternatively, the slit can include an interlockingfastener. The insulator can also include a spiral slit with or withoutan associated fastener.

[0015] The present invention also provides an apparatus for protectingand insulating joints in a vacuum insulated tubing string, where theapparatus includes an insulator sleeve having a longitudinal slit, asubstantially smooth outer surface, and an inner surface that conformsto an outer contour of the joint and to a portion of the tubing oneither side of the joint. The apparatus also includes a joint protectorhaving a first latching end and second latching end where the latchingends are adapted to secure the protector to the vacuum insulated tubingstring on both sides of the joint. The protector also includes a centerregion having a plurality of insulator retaining members, where thecenter region is adapted to hold the insulator against the joint. Theprotector also includes a conduit adapted to receive injection orcontrol tubing allowing injection and/or control tubing to pass over thejoint in a protected manner. The insulator can also include a strip ofadhesive adapted to seal the longitudinal slit. Alternatively, the slitcan include an interlocking fastener. The insulator can also include aspiral slit with or without an associated fastener.

[0016] The present invention also provides an apparatus for protectingand insulating joints in a vacuum insulated tubing string, where theapparatus includes an insulator sleeve having a longitudinal slit, asubstantially smooth outer surface, and an inner surface that conformsto an outer contour of the joint and to a portion of the tubing oneither side of the joint. The apparatus also includes a joint protectorhaving a first latching end and second latching end where the latchingends are adapted to secure the protector to the vacuum insulated tubingstring on both sides of the joint. The protector also includes a centerregion having a plurality of insulator retaining members, where thecenter region is adapted to hold the insulator against the joint. Theprotector also includes a conduit adapted to receive injection orcontrol tubing allowing injection and/or control tubing to pass over thejoint in a protected manner. The insulator can also include a strip ofadhesive adapted to seal the longitudinal slit. Alternatively, the slitcan include an interlocking fastener. The insulator can also include aspiral slit with or without an associated fastener.

[0017] The present invention provides an apparatus including aninsulator adapted to conform to the outer contour of the joint and aportion of the tubing on either side of the joint and a protectorincluding a pair of half-cylinder shaped sections which areinterconnected at respective edges by an elongate piano-type hingehaving a releasable pin. The opposite edges are provided with aplurality of pin guide sections matingly received by each other todefine a pair of longitudinal pin slots when the protector is disposedabout a tool joint. A pair of mating tapered pins are provided for eachslot whereby when the pins are driven into their respective slots, theedges of the half-sections carrying the pin guides are drawn toward eachother to effect progressively tighter engagement of the protector aboutthe tool joint and tubing in an interference fit. Half-sections ofvarying radii of curvature and pins of varying taper are provided,whereby a variety of tool joints having differing outer dimensions maybe accommodated, resulting in an effective interference fit bysubstituting half-sections and pins of appropriate size. A windowintermediate the pair of pin slots facilitates lower pin installationwhile providing for slight flexing of the protector about the tool jointto further accommodate dimensional variations thereof.

[0018] The present invention provides a protected and insulated vacuuminsulated tubing string including a vacuum insulated tubing stringhaving a plurality of vacuum insulated tubing sections interconnected byjoints and an insulating apparatus of this inventio associated with eachjoint.

DESCRIPTION OF THE DRAWINGS

[0019] The invention can be better understood with reference to thefollowing detailed description together with the appended illustrativedrawings in which like elements are numbered the same:

[0020] FIGS. 1A-F depict views of a preferred embodiment of theinsulating apparatus of this invention detachably affixed to a joint ofa vacuum insulated tubing string;

[0021]FIG. 1G depicts a cut away view of an insulator of this inventionhaving a lower surface that conforms to a recess in the joint of avacuum insulated tubing string;

[0022]FIG. 2A-F depict views of another preferred embodiment of theinsulating apparatus of this invention detachably affixed to a joint ofa vacuum insulated tubing string;

[0023]FIG. 3A-F depict views of another preferred embodiment of theinsulating apparatus of this invention detachably affixed to a joint ofa vacuum insulated tubing string;

[0024]FIG. 4A-D depict views of another preferred embodiment of theinsulating apparatus of this invention detachably affixed to a joint ofa vacuum insulated tubing string; and

[0025]FIG. 5A-F depict other preferred embodiment of insulators of thisinvention.

DETAILED DESCRIPTION OF THE INVENTION

[0026] The inventors have found that heat loss from joints of a vacuuminsulated tubing string can be reduced by as must as 95% or more bydetachably affixing to each joint an insulating apparatus including aninsulator adapted to conform to an outer surface of the joint andpreferably to conform to a portion of the tubing on either side of eachjoint and a joint/insulator protector adapted to be interference fit tothe tubing on either side of each joint, to secure the insulator inplace and to provide a protected conduit for injection and controltubing. Thus, the inventors have found that a vacuum insulated tubingstring can be formed including an insulator protector of this inventionassociate with each joint in the string reducing heat loss through thejoints by as much as 95%.

[0027] The present invention broadly relates an insulator apparatus foruse with vacuum insulated tubing strings, where the apparatus includesan insulator adapted to insulate joints in the vacuum insulating tubingstring and a joint protector adapted to secure the insulator against thejoints, to protect the joints from damage during run in and run out andto provide a protected conduit adapted to receive injection or controltubing associated with the vacuum insulated tubing.

[0028] The present invention broadly relates to a method for reducingheat loss at joint in a vacuum insulated tubing string including thestep of detachably affixing to each joint of the string an insulatorapparatus for use with vacuum insulated tubing strings, where theapparatus includes an insulator adapted to insulate joints in the vacuuminsulating tubing string and a joint protector adapted to secure theinsulator against the joints, to protect the joints from damage duringrun in and run out and to provide a protected conduit adapted to receiveinjection or control tubing associated with the vacuum insulated tubing.

[0029] The present invention broadly relates to a vacuum insulatedtubing string including a vacuum insulated tubing string having aplurality of vacuum insulated tubing sections interconnected by jointsand an insulating apparatus of this invention associated with eachjoint.

[0030] Suitable polymers for making the insulators of the presentinvention include, without limitation, insulating polymeric and/orceramic materials. Preferred polymeric materials include, withoutlimitation, thermal setting resins, thermoplastic elastomers,thermoplastics, or any other polymeric material or mixtures orcombinations thereof, where the polymers good insulating properties andcan be cast or molded by any standard casting or molding techniqueincluding traditional polymer casting, traditional molding, rotarymolding, injection molding, or the like. Moreover, for structuralplastics, the insulator can be cut using traditional cutting techniques.Preferred thermal setting resins include polyurethanes, elastomers, orthe like. Preferred thermoplastics include structural plastics such asstructure polyolefins exemplified by plastics such as high densitypolyethylene, polypropylene, polybutylene, polystyrenes, polyesters,polyurethanes, polyvinylchlorides, polyacrylates, nylons and otherpolyamides (Kevlar, Nomex), or the like. Preferred polyacrylatesincludes acetal resins such as Delrin® from DuPont or other similarinjection moldable polymers. The polymers should have a thermalconductivity at or below about 0.5 W/m° C. at 100° C., preferably at orbelow about 0.4 W/m° C. at 100° C., and particularly at or below about0.3 W/m° C. at 100° C. Exemplary polyurethanes include precisionurethane with short hardnesses of 45A to about 100A including urethanesavailable from the manufacturers listed on the world wide web aturethane-ez.com/urethane. Preferred urethane polymers should have atensile strength between about 4,000 psi and about 14,000 psi at 75° F.,a 100% modulus of elasticity at 75° F. between about 1,000 psi and about550,000 psi, and an elongation of about at 75° F. between about 30% and1000. Particularly preferred urethanes have the physical characteristicslisted in Table IA-B. TABLE IA Physical Properties of PreferredUrethanes Urethane 90A PPG Urethane 90A PTMEG Property 0° 75° 150° F. 0°75° 150° F. Modulus, 4142 1083 967 1194 1140 956 100%, psi Modulus, 50091673 1303 1701 1612 1241 200%, psi Modulus, 2530 2528 2416 1600 300%,psi Tensile 5851 3167 1764 7244 5446 2025 Strength, psi % Elongation 263330 293 393 396 332 Die C Tear, psi 660 189 126 390 306 220 TrouserTear, 188 48 23 108 66 27 psi Bashore 29 43 Resilience, % Compression 3124 Set, % (Method B) Compression 32 57 Stress @ 1%, psi Modulus of N/A3559 Rigidity, psi Young's 6800 5097 Modulus, psi Shear Modulus, N/A1700 psi Bulk Modulus, N/A 9.9 × 10³ psi Poisson's Ratio 0.475 0.499

[0031] TABLE IB Specific Heat and Thermal Conductivity Properties of thePreferred Urethanes Urethane 90A PPG Urethane 90A PTMEG Specific HeatTemperature Heat Flow Temperature Heat Flow ° C. J/kg · ° C. ° C. J/kg ·° C. 20 −1729 10 −1544 40 −1803 30 −1669 60 −1844 50 −1690 80 −1897 70−1716 100 −1913 90 −1720 120 −1907 100 −1710 140 −1885 130 −1713 ThermalConductivity Temperature Conductivity Temperature Conductivity ° C. W/m· ° C. ° C. W/m · ° C. 100 0.276 60.4 0.208 125 0.266 68.5 0.202 1500.259 100.7 0.213 175 0.253 126.9 0.215

[0032] Suitable materials out of which the protectors of this inventioncan be made include, without limitation, metals especially iron alloyssuch as forged steel, stainless steel, or the like. Generally, theinsulators are desinged to decrease heat loss from the joint of a vacuuminsulated tubing by 50% or more, preferably, by 75% or more,particularly, by 85% or more and especially by 90% or more.

Insulating Apparatus for Recessed Jointed Vacuum Insulated Tubing

[0033] Referring now to FIGS. 1A-F, a preferred embodiment of aninsulating apparatus, generally 100, of this invention is showndetachably affixed to a joint 102 of a vacuum insulated productionstring 104. The string 104 is shown with a first string section 106 aand a second string section 106 b. The tube sections 106 a&b includeinner tubes 108 b&b and outer tubes 110 a&b with vacuum gaps 112 a&binterposed therebetween except at the joint 102 where the outer tubes110 a&b end forming a recessed area 114. The joint 102 is formed from afemale connector 116 formed out of a distal end 118 of the inner tube108 a of the first tube section 106 a and a male connector 120 formedout of a proximal end 122 of the inner tube 108 b of the second tubesection 106 b. Because the joint 102 does not include a vacuum gap, heatcan flow from an interior 124 of the string 104 to the surroundings, aproblem to be avoided and a problem solved by the apparatuses of thisinvention.

[0034] The insulating apparatus includes an insulator 140 and a latchingprotector 160. The insulator 140 comprises a cylinder sleeve 142 havinga longitudinal slit 144 where the slit 144 allows the sleeve 142 to beopened and fitted into the recess 114. The slit 144 can be left as is orcan be sealed by an insulating sealing compound such as a fast dryingthermoplastic, thermosetting resin, other polymeric insulating materialor mixtures or combinations thereof. Although the sleeve 142 of FIGS.1A-F is cylindrical with straight edges 146, the sleeve 142 can bedesigned to conform to the recess 114 so that its edges 146 are nowtapered as shown in FIG. 1G.

[0035] The protector 160 includes two hinges 162, a raised portion 164separating the two hinges 162, two arcuate sections 166 and aninterdigitated latch 168 having a first end 170 and a second end 172adapted to receive a key 174, which locks the protector 160 in placewith an interference fit. The latch 168 and key 174 are defined in moredetail in U.S. Pat. No. 4,615,543, incorporated therein by reference.When the protector 160 is placed around the insulator 140 and closed,the key 174 is inserted into the interdigitated latch 168 in such a waythat the key 174 pulls the latch 168 together creating an interferencefit against the insulator 160 and/or the sections 106 a&b. The raisedportion 164 forms a protected channel 176 adapted to receive injectionand/or control tubing, lines, or cables 178 and can include a cushion180 on its inner surface 182.

[0036] Referring now to FIGS. 2A-F, another preferred embodiment of aninsulating apparatus, generally 200, of this invention is showndetachably affixed to a joint 202 of a vacuum insulated productionstring 204. The string 204 is shown with a first string section 206 aand a second string section 206 b. The tube sections 206 a&b includeinner tubes 208 b&b and outer tubes 210 a&b with vacuum gaps 212 a&binterposed therebetween except at the joint 202 where the outer tubes210 a&b end forming a recessed area 214. The joint 202 is formed from afemale connector 216 formed out of a distal end 218 of the inner tube208 a of the first tube section 206 a and a male connector 220 formedout of a proximal end 222 of the inner tube 208 b of the second tubesection 206 b. Because the joint 202 does not include a vacuum gap, heatcan flow from an interior 224 of the string 204 to the surroundings, aproblem to be avoided and a problem solved by the apparatuses of thisinvention.

[0037] The insulating apparatus includes an insulator 240 and a latchingprotector 260. The insulator 240 comprises a cylinder sleeve 242 havinga longitudinal slit 244, a substantially straight outer surface 246 andan inner surface 248 that conforms to the recess 214 and to portions 250of the sections 206 a&b. Thus, the inner surface 248 includes an raisedsection 252 conforming to the recess 214 and wings 254 extending overthe portions 250 of the section 206 a&b, where the portions 250 extendout a sufficient distance from the joint 202 to provide improved jointinsulation, where the sufficient distance is at least sufficient toextend past the start of the vacuum gaps 210 a&b. The insulator 240 alsoincludes a groove 256 for receiving injection and/or control tubing ?.The slit 244 allows the sleeve 242 to be opened and the conformingraised section 252 of the inner surface 248 of the insulator 240 fittedinto the recess 214, with the wings 254 extending over the portions 250.The slit 244 can be left as is or can be sealed by an insulating sealingcompound such as a fast drying thermoplastic, thermosetting resin, otherpolymeric insulating material or mixtures or combinations thereof.

[0038] The protector 260 includes two latching ends 262 having twohinges 264, a raised portion 266 separating the two hinges 264, andouter tube engaging members 268. The protector 260 also includeslongitudinally extended arcuate sections 270 interconnecting thelatching ends 262 and the latching ends 262 also include aninterdigitated latch 272 having a first digitated end 274 and a seconddigitated end 276 adapted to receive a key 278, which locks theprotector 260 in place with an interference fit. The latches 272 andkeys 278 are defined in more detail in U.S. Pat. No. 4,615,543,incorporated therein by reference. When the protector 260 is placedaround the insulator 240 and joint 202 and closed, the keys 278 areinserted into the interdigitated latches 272 in such a way that the keys278 pull the latches 272 together creating an interference fit againstthe string 202 on each side of each joint. The raised portion 266 formsa protected channel 280 adapted to receive injection and/or controltubing, lines, or cables 282 and can include a cushion 284 on its innersurface 286.

Insulating Apparatus for Raised Jointed Vacuum Insulated Tubing

[0039] Referring now to FIGS. 3A-F, another preferred embodiment of aninsulating apparatus, generally 300, of this invention is showndetachably affixed to a joint 302 of a vacuum insulated productionstring 304. The string 304 is shown with a first string section 306 aand a second string section 306 b. The tube sections 306 a&b includeinner tubes 308 b&b and outer tubes 310 a&b with vacuum gaps 312 a&binterposed therebetween except at the joint 302 where the outer tubes310 a&b end forming a recessed area 314. The joint 302 is formed from ajoint collar 316 having two female end connectors 318 adapted to receivemale connectors 320 associated with the tube sections 306 a&b. The jointcollar 316 is larger than the section 306 a&b forming a raised jointsection 322. Because the joint 302 does not include a vacuum gap, heatcan flow from an interior 324 of the string 304 to the surroundings, aproblem to be avoided and a problem solved by the apparatuses of thisinvention.

[0040] The insulating apparatus includes an insulator 340 and a latchingprotector 360. The insulator 340 comprises a cylinder sleeve 342 havinga longitudinal slit 344. The sleeve 342 also includes a groove 346adapted to conform to the raised joint section 322 of the joint 302. Thesleeve 342 also includes end portions 348 that extend past the jointcollar 316 over portions 350 of the section 306 a&b, where the portions350 extend out a sufficient distance from the joint 302 to provideimproved joint insulation, where the sufficient distance is at leastsufficient to extend past the start of the vacuum gaps 310 a&b of thesection 306 a&b. The slit 344 allows the sleeve 342 to be opened andfitted into the recess 314. The slit 344 can be left as is or can besealed by an insulating sealing compound such as a fast dryingthermoplastic, thermosetting resin, other polymeric insulating materialor mixtures or combinations thereof.

[0041] The protector 360 includes two latching ends 362 having twohinges 364, a raised portion 366 separating the two hinges 364, andouter tube engaging members 368. The protector 360 also includeslongitudinally extended members 370 interconnecting the latching ends362. The latching ends 362 also include interdigitated latches 372, eachlatch 372 having a first digitated end 374 and a second digitated end376 adapted to receive a key 378, which locks the protector 360 in placewith an interference fit. The latches 372 and keys 378 are defined inmore detail in U.S. Pat. No. 4,615,543, incorporated therein byreference. When the protector 360 is placed around the insulator 340 andjoint 302 and closed, the keys 378 are inserted into the interdigitatedlatches 372 in such a way that the keys 378 pull the latches 372together creating an interference fit against the string 302 on eachside of each joint. The raised portion 366 forms a protected channel 380adapted to receive injection and/or control tubing, lines, or cables 382and can include a cushion 384 on its inner surface 386.

Alternate Protector Design

[0042] Referring now to FIGS. 4A-D, another preferred embodiment of aninsulating apparatus, generally 400, of this invention is shown toinclude detachably affixed to a joint (not shown) of a vacuum insulatedproduction string 402 within a cased well 404. The insulating apparatusincludes an insulator 440 and a latching protector 460. The insulator440 comprises a cylinder sleeve 442 having a longitudinal slit 444 wherethe slit 444 allows the sleeve 442 to be opened and fitted over eachjoint of the string 402. The slit 444 can be left as is or can be sealedby an insulating sealing compound such as a fast drying thermoplastic,thermosetting resin, other polymeric insulating material or mixtures orcombinations thereof. Moreover, as shown below the slit does not have tobe straight and can be formed with fastening or interlocking ends.

[0043] The protector 460 includes two latching ends 462 having twohinges 464, an arcuate portion 466 separating the two hinges 464, andouter tube engaging members 468. The protector 460 also includes foursubstantially parallel, longitudinally extended members 470interconnecting the latching ends 462 so that the insulator 440 is heldin place by the four members 470. The latching ends 462 also includeinterdigitated latches 472, each latch 472 having a first digitated end474 and a second digitated end 476 adapted to receive a key 478, whichlocks the protector 460 in place with an interference fit. The latches472 and keys 478 are defined in more detail in U.S. Pat. No. 4,615,543,incorporated therein by reference. When the protector 460 is placedaround the insulator 440 and joint 402 and closed, the keys 478 areinserted into the interdigitated latches 472 in such a way that the keys478 pull the latches 472 together creating an interference fit againstthe string 402 of either side of each joint. The arcuate portion 466forms a protected channel 480 adapted to receive injection and/orcontrol tubing, lines, or cables 482 and can include a cushion 484 onits inner surface 486. The protector 460 also includes a raisedinjection and/or control tubing conduit 488 also interconnecting the twoends 462. Thus, the member 470 and the conduit 488 structurally hold thetwo ends 462 of the protector 460.

Alternate Insulator Designs

[0044] Referring now to FIGS. 5A-F, several other preferred embodimentof insulators 500 of this inventor are shown. Looking at FIG. 5A, theinsulator 500 includes a zig-zagged slit another 502. Looking at FIG.5B, the insulator 500 includes a spiral slit 504. Looking at FIG. 5C,the insulator 500 includes a slit 506 having a fastener 508. Thefastener 508 includes a male connector 510 associated with a first end512 of the insulator 500 and a female connector 514 associated with asecond end 516 of the insulator 500. Looking at FIG. 5D, the insulator500 includes a slit 518 having a fastener 520. The fastener 520 includesan inner longitudinal lip 522 associated with a first end 524 of theinsulator 500 and an outer longitudinal lip 526 associated with a secondend 528 of the insulator 500. Looking at FIG. 5E, the insulator 500includes a slit 530 having a fastener 532. The fastener 532 includes aninner longitudinal lip 534 having a longitudinal groove 536 associatedwith a first end 538 of the insulator 500 and an outer longitudinal lip540 having a longitudinal indentation 542 associated with a second end544 of the insulator 500. Looking at FIG. 5F, the insulator 500 includesa slit 546 having an interlocking fastener 548. The interconnectingfastener 548 includes an inner longitudinal lip 550 having longitudinalgrooves 552 associated with a first end 554 of the insulator 500 and anouter longitudinal lip 556 having longitudinal indentations 558associated with a second end 560 of the insulator 500, where the grooves552 are designed to receive the indentations 558 to form a lockingfastener. Although several insulators with slit ends designed to engageeach other in a substantially gap free manner have been described, anyother fastening or means for bring the slit end together in asubstantially gap free manner.

[0045] All references cited herein are incorporated by reference. Whilethis invention has been described fully and completely, it should beunderstood that, within the scope of the appended claims, the inventionmay be practiced otherwise than as specifically described. Although theinvention has been disclosed with reference to its preferredembodiments, from reading this description those of skill in the art mayappreciate changes and modification that may be made which do not departfrom the scope and spirit of the invention as described above andclaimed hereafter.

We claim:
 1. An insulating apparatus for insulating joints of a vacuuminsulated tubing string comprising an insulator adapted to surroundjoints of the vacuum insulated tubing string and a latching jointprotector adapted to surround the insulator and hold the insulatoragainst the joint, where the protector also includes a channel forreceiving injection tubing, control tubing or a combination of injectionand control tubing.
 2. The apparatus of claim 1, wherein the insulatorcomprises a cylindrical sleeve including a longitudinal slit.
 3. Theapparatus of claim 1, wherein the insulator comprises a cylindricalsleeve including a longitudinal slit, a substantially straight outersurface and an inner surface conforming to an outer surface of thejoint.
 4. The apparatus of claim 1, wherein the insulator comprises acylindrical sleeve including a longitudinal slit, a substantiallystraight outer surface and an inner surface conforming to an outersurface of the joint and to portions of the string on either side of thejoint.
 5. The apparatus of claim 1, wherein the insulator comprises acylindrical sleeve including a longitudinal slit, a substantiallystraight outer surface and an inner surface having a joint conformingmiddle section and wings conforming to portions of the string on eitherside of the joint and extending out away from the joint a sufficientdistance to overlap with a section of the string including a vacuum gapbetween an inner tube and an outer tube of the string.
 6. A vacuuminsulated tubing string comprising: a plurality of tubing section, eachof the sections including an inner tube, an outer tube, a vacuum gapinterposed therebetween, a first connector associated with a first endof each section and a second connector associated with a second end ofeach section, where the connectors on adjacent sections either directlyform a joint or form a joint with a joint collar interconnecting thesection connectors; and a plurality of insulating apparatuses, eachapparatus adapted to surround one of the joints of the string and alatching joint protector adapted to surround the insulator and hold theinsulator against its associated joint, where the protector alsoincludes a channel for receiving injection and/or control tubing.
 7. Theapparatus of claim 6, wherein the insulator comprises a cylindricalsleeve including a longitudinal slit.
 8. The apparatus of claim 6,wherein the insulator comprises a cylindrical sleeve including alongitudinal slit, a substantially straight outer surface and an innersurface conforming to an outer surface of the joint.
 9. The apparatus ofclaim 6, wherein the insulator comprises a cylindrical sleeve includinga longitudinal slit, a substantially straight outer surface and an innersurface conforming to an outer surface of the joint and to portions ofthe string on either side of the joint.
 10. The apparatus of claim 6,wherein the insulator comprises a cylindrical sleeve including alongitudinal slit, a substantially straight outer surface and an innersurface having a joint conforming middle section and wings conforming toportions of the string on either side of the joint and extending outaway from the joint a sufficient distance to overlap with a section ofthe string including a vacuum gap between an inner tube and an outertube of the string.
 11. A method for reducing heat loss from a vacuuminsulated tubing string comprising the step of detachably affixing toeach joint of the string an insulating apparatus comprising an insulatoradapted to surround the joint and a latching joint protector adapted tosurround the insulator and hold the insulator against the joint, wherethe protector also includes a channel for receiving injection and/orcontrol tubing.
 12. The method of claim 11, wherein the insulatorcomprises a cylindrical sleeve including a longitudinal slit.
 13. Themethod of claim 11, wherein the insulator comprises a cylindrical sleeveincluding a longitudinal slit, a substantially straight outer surfaceand an inner surface conforming to an outer surface of the joint. 14.The method of claim 11, wherein the insulator comprises a cylindricalsleeve including a longitudinal slit, a substantially straight outersurface and an inner surface conforming to an outer surface of the jointand to portions of the string on either side of the joint.
 15. Themethod of claim 11, wherein the insulator comprises a cylindrical sleeveincluding a longitudinal slit, a substantially straight outer surfaceand an inner surface having a joint conforming middle section and wingsconforming to portions of the string on either side of the joint andextending out away from the joint a sufficient distance to overlap witha section of the string including a vacuum gap between an inner tube andan outer tube of the string.